1. Field of the Invention
The invention relates generally to coffee brewing devices of the infusion or drip type and more specifically to devices which are adapted to brew and deposit a single serving of coffee beverage into a drinking cup.
2. Brief Description of the Prior Art
Generally, devices which brew coffee in accordance with the drip method were designed to permit the passage of a premeasured quantity of hot water through a quantity of roasted and ground coffee and into a lower collection vessel. During the brewing process the brewing water flowed by gravity through a predetermined course.
In some of the prior drip method brewing devices, the coffee was positioned within a basket and was separated from both the brewing water and the collection container by perforated walls which permitted the passage of the brewing water and coffee beverage.
Further drip brewing apparatus permitted the immediate comingling of brewing water and coffee, yet provided filtration means to remove coffee grounds from the coffee beverage. The filtration means generally used was a paper filter disc, usually folded to a conical shape so that it generally conformed to a conical water container.
With the use of some of these previous drip brewing devices, the coffee brewage from a given measure of coffee often tended to be generally weaker than that utilizing alternate brewing apparatus and additional quantities of coffee were necessary to provide a satisfactory brew. This was in part attributable to the uncontrolled expansion of the coffee upon contact with the hot water resulting in an unfavorable extraction rate. Thus, if one desired a coffee beverage of a particular strength, often more coffee would be needed when utilizing a drip brewer than when, for instance, utilizing a perk method brewer.
Although drip brewing devices have been provided in small sizes which were particularly adapted for single servings, these devices did not gain widespread acceptance for a number of reasons. Initially, it should be appreciated that the unfavorable extraction rate was not compensated or rectified with prior single serving drip brewers.
Some single serving disposable devices included a premeasured packet of ground coffee. In order to provide effective extraction, the filter bags or other filter containers within which the coffee was carried required relatively large openings. Unfortunately, the mesh size required permitted the settling of coffee fines through the filter during shipping and handling. This condition was commonly termed dusting and, of course, was undesirable.
A further problem encountered with single serving drip brewing devices, especially with disposable or throwaway types, was that costs could not be brought to commercially feasible levels. In fact, the estimated retail prices of these prior devices were comparable to restaurant prepared coffee beverage obtained at take-out counters. When weighing this factor with the inconvenience of heating water for single serving brewers and the cleaning up of cups and utensils, it is not surprising that such prior brewers were not accepted.
A further problem encountered with prior single serving drip brewers was that several were either designed to fit only over a specific size companion drinking vessel or were so constructed as to be only usable with a limited range of cup shapes and/or sizes.
With the nondisposable drip brewers, the inconvenience of measuring the ground coffee and cleaning up the coffee grinds after usage overcame the taste advantage of utilizing fresh ground coffee for drip method single serving brewers. A further factor relating to the lack of commercial success was that the ease and convenience of making a coffee beverage with instant coffee far outweighed the palatable advantages of single serving brewed coffee.